Deviant motion of the eye at the first several harmonics of the heat rate may be indicative of circulatory problems within the head and neck area. Since an acoustic wave travelling in air is totally reflected by any liquid or solid surface, it is practical to interrogate the front surface of the eye by means of ultrasound. The phase delay between separate transmitting and receiving transducers is modulated by the eye motion. This delay is converted to amplitude modulation and recorded, resulting in a record of eye motion vs. time.